Pneumatic feeders of the type shown in my U.S. Pat. No. 3,329,327 have relied on the use of a variable air flow restriction in the pressure fluid (air) conducting line to the head end of the main cylinder in order to afford not only feed speed adjustments but also the time delay action needed for sequencing the execution of the stock gripping and clamping actions with respect to the stock feeding action of the feeder.
Although this arrangement has for the most part given satisfactory results further control refinements are desireable to accommodate some of the current operational and user requirements. Furthermore all air feeds have certain set up requirements such as the need for (a) proper synchronization of the feeder operation with the press operation, and (b) the capacity for fine adjustment of the feed stroke length which in many cases must be very precisely made particularly in connection with high and/or exacting performance operations and which can be tedious to manually establish. Thus it is desireable to maximize these aspects of air feed construction and operation.